Fuse blows, nothing works

Hi, seeking advice on how to fix my Sr10. I bought it used and it got off one shot and it never worked since. Thought it was the lipo, but the battery I bought to replace it reacted the same way as the lipo, killing the fuse. There is no sign that any of the electrically work, the battery and connector just turns hot and the fuse blows. I replace the fuse and plugin any of the batteries (that are all OK'ed for use with the KM) and it just blows the fuse immediately.

I am not too sure what to do to even attempt fixing the problem. Would much prefer to not have to send it back, hopefully by just replacing something.

Hi, seeking advice on how to fix my Sr10. I bought it used and it got off one shot and it never worked since. Thought it was the lipo, but the battery I bought to replace it reacted the same way as the lipo, killing the fuse. There is no sign that any of the electrically work, the battery and connector just turns hot and the fuse blows. I replace the fuse and plugin any of the batteries (that are all OK'ed for use with the KM) and it just blows the fuse immediately.

I am not too sure what to do to even attempt fixing the problem. Would much prefer to not have to send it back, hopefully by just replacing something.

Any help appreciated!

Hi Heathrow, welcome to the KWA Forums. It could be a number of things. The gearbox could be jammed which can be caused by any number of internal parts failure. However, based only on the post and the information provided, it may be a pinched wire. Most likely that wire would be at the base of the buffer tube where it joins the lower receiver. Has the gun been opened or modified in any way? Heck, it could even be incorrect polarity (switched wires) at the battery connector or on the motor.

Thanks for this! Will take your advice step by step and see if I can fix.

gcw360, on 10 May 2013 - 07:31 PM, said:

Hi Heathrow, welcome to the KWA Forums. It could be a number of things. The gearbox could be jammed which can be caused by any number of internal parts failure. However, based only on the post and the information provided, it may be a pinched wire. Most likely that wire would be at the base of the buffer tube where it joins the lower receiver. Has the gun been opened or modified in any way? Heck, it could even be incorrect polarity (switched wires) at the battery connector or on the motor.

I took a methodical approach and found that wires seemed to be cross-connected, black to red and vice versa. Even though I swapped it didn't fix the problem. Took the motor out of the grip and when pushing the trigger, the motor ran. So it seems the gearbox was not connecting well to the motor or something in there is obstructing.

I am now trying to disassemble the gearbox, but maybe some of you out there has a tip that I overlooked before I mess it all up?

The fuse obviously died because the motor was blocked. But is there something I don't know?

Thanks for your time...

gcw360, on 10 May 2013 - 07:31 PM, said:

Hi Heathrow, welcome to the KWA Forums. It could be a number of things. The gearbox could be jammed which can be caused by any number of internal parts failure. However, based only on the post and the information provided, it may be a pinched wire. Most likely that wire would be at the base of the buffer tube where it joins the lower receiver. Has the gun been opened or modified in any way? Heck, it could even be incorrect polarity (switched wires) at the battery connector or on the motor.

Here's what I think the issue may be and it boils down to several possibilities:

Reversed polarity - You may have solved this already but let's be sure

Weak/damaged battery

Seized gearbox

Motor needs maintenance

There are two holes in the plug that the wires go through. A round one (+) and a square one (-). To ensure the polarity is correct, and assuming you have mini Tamiya plugs in the battery and gun, confirm that the red (+) wire is going through the "round" port in the plug. Next be certain that the red motor wire is on the positive terminal of the motor. This terminal is marked in red and with a "+" sign. If this is all in order then move on the the other possibilities I mention below.

To check for a jammed GB, open the upper receiver and look at the position of the piston. If it is in the rear or locked position, or in between cycles, it may very well be jammed. This can occur with any number of parts failures including but not limited to:

Broken piston

Broken gears

Blown barrings

Foreign body in the drive train

Another cause can be a weak, undercharged, or damaged battery. In this case the battery can not deliver enough power to cycle this piston.

Lastly, the motor brushes could be gunked up an not allowing enough current to the motor.
I know I posed some of this before, but I though more detail might be helpful.

In all the cases above, you should hear the motor try to engage and give a "click, click" noise with each trigger pull.

Hope this helps and keep us posted.

PS. One last thought, if the motor height ins not properly adjusted so that the motor is going to far into the handle it will cause the gearbox to seize. This is caused by the motor height screw being to far or the motor wires pushing the motor too far down into the handle. It's an easy fix though and the seize should be temporary and resolved with proper motor height adjustment.

Polarity seems fine, have two batteries, each of them fully charged and able. I tried to adjust the motor height in all increment and blew another fuse doing it. It seems like something is stuck in the gearbox.

Can I send the gearbox to KWA for repairs? How does that work. Again, your Tim is very much appreciated!

Tn

gcw360, on 14 July 2013 - 04:30 PM, said:

Here's what I think the issue may be and it boils down to several possibilities:

Reversed polarity - You may have solved this already but let's be sure

Weak/damaged battery

Seized gearbox

Motor needs maintenance

There are two holes in the plug that the wires go through. A round one (+) and a square one (-). To ensure the polarity is correct, and assuming you have mini Tamiya plugs in the battery and gun, confirm that the red (+) wire is going through the "round" port in the plug. Next be certain that the red motor wire is on the positive terminal of the motor. This terminal is marked in red and with a "+" sign. If this is all in order then move on the the other possibilities I mention below.

To check for a jammed GB, open the upper receiver and look at the position of the piston. If it is in the rear or locked position, or in between cycles, it may very well be jammed. This can occur with any number of parts failures including but not limited to:

Broken piston

Broken gears

Blown barrings

Foreign body in the drive train

Another cause can be a weak, undercharged, or damaged battery. In this case the battery can not deliver enough power to cycle this piston.

Lastly, the motor brushes could be gunked up an not allowing enough current to the motor.
I know I posed some of this before, but I though more detail might be helpful.

In all the cases above, you should hear the motor try to engage and give a "click, click" noise with each trigger pull.

Hope this helps and keep us posted.

PS. One last thought, if the motor height ins not properly adjusted so that the motor is going to far into the handle it will cause the gearbox to seize. This is caused by the motor height screw being to far or the motor wires pushing the motor too far down into the handle. It's an easy fix though and the seize should be temporary and resolved with proper motor height adjustment.

Interests:Keeping those damn squirrels from putting their filthy little paws on my peaches in my backyard. Oh, Yes. It's not just a hobby, its a passion!!

Country:

Posted 18 July 2013 - 08:39 AM

Jump on the "helpdesk" and create an account. After logging in fill out a repair ticket with all info requested. KWA will send you instructions on what to do and you will receive a RMA number. Then you just follow the instructions given and send to KWA.

Jump on the "helpdesk" and create an account. After logging in fill out a repair ticket with all info requested. KWA will send you instructions on what to do and you will receive a RMA number. Then you just follow the instructions given and send to KWA.

Thanks guys. I did end up taking the gearbox apart and this is what I saw. I am in fact right in the middle of messing with it so let me know if you can spot the problem. Seems the spring was wound back and stuck...ImageUploadedByTapatalk1374438444.610446.jpg162.97K11 downloads

Please pull the piston out so we can see the piston head and show the cylinder assembly. There is something funky going on with the cylinder/piston. The sector gear doesn't look like it's engaging the piston yet it is back. that's odd...unless I'm just misreading the photo.

So again, I would like to thank you guys for helping out. I took it apart, put it all together again and it still was jammy. Then I took out the bottom plate of the grip and just held the motor with my fingers and it worked! So I put the bottom plate in but really conservatively screwed in and now it shoots. For the first time! It is magical. I have had this gun for 4 months without ever firing off one shot. So again thanks!

When I took it apart I found one little foam bit from the box it came with, inside the piston thingie. Not sure if that could have caused it to jam?

gcw360, on 21 July 2013 - 05:02 PM, said:

Please pull the piston out so we can see the piston head and show the cylinder assembly. There is something funky going on with the cylinder/piston. The sector gear doesn't look like it's engaging the piston yet it is back. that's odd...unless I'm just misreading the photo.

Interests:Keeping those damn squirrels from putting their filthy little paws on my peaches in my backyard. Oh, Yes. It's not just a hobby, its a passion!!

Country:

Posted 26 July 2013 - 08:53 AM

The bit of styrofoam will not cause the gear box to seize so I don't think that is it.
And sometimes for no good reason a complete disassembly and reassembly resolves issues. I don't know what it is...................it could be KWA gremlins.